As methods for analyzing phosphorylated substances, for example, phosphorylated biological substances, a method using enzyme-linked immunosorbent assay and a method using a radioisotope have conventionally been known. In the analysis of phosphorylated biological substances, a substance is desired which has a property such that the substance strongly binds to a phosphate monoester dianion as an anionic substituent under predetermined conditions and a property such that the resultant complex is detectable, and which is safe and inexpensive.
As a method for lowering the phosphate concentration of waste water, there is a method using a composite metal hydroxide disclosed in Japanese Unexamined Patent Publication No. Hei. 11-57695. In the field of medicine, as a substance used for the medical treatment of hyperphosphatemia, there is a polymer having a guanidino group disclosed in Japanese Unexamined Patent Publication No. Hei. 8-506846. A substance is desired which binds more strongly to phosphate and which is safer and more inexpensive than the composite metal hydroxide or a polymer having a guanidino group.
However, such a substance has not been known, which strongly binds to a phosphate monoester dianion to form a complex detectable and which is safe and inexpensive.
The enzyme-linked immunosorbent assay, which is one of the methods for analyzing a phosphorylated biological substance, utilizes the action of an antibody which specifically binds to a desired substance. Therefore, there is a need to prepare an antibody specific to the desired substance. The preparation of the antibody has a problem in that a great amount of the desired substance must be purified and obtained. In addition, the preparation of the antibody uses immune response of an animal and hence causes a problem in that a prolonged period of time is required to prepare the same. Further, an antibody for a phosphorylated site in a molecular structure with several kDa (daltons) or less cannot be prepared, and therefore a problem arises in that a phosphorylated biological substance having such a small molecular structure cannot be analyzed by enzyme-linked immunosorbent assay.
In the method for analyzing a phosphorylated biological substance using a radioisotope, radioisotope 32P is used. Therefore, there is a disadvantage in that handling of radiation in laboratories and management of waste liquor are cumbersome.
Further, the composite metal hydroxide used for lowering the phosphate concentration of waste water and the polymer having a guanidino group used for the medical treatment of hyperphosphatemia individually have only a poor ability to bind to a phosphate group. Therefore, for capturing a certain amount of a phosphate, a large amount of the composite metal hydroxide or the polymer having a guanidino group must be used as a phosphate-group bind substrate.
In view of the above problems accompanying the prior art, the present invention has been made, and an object is to provide a safe and inexpensive substance which binds to an anionic substituent, especially a phosphate monoester dianion under predetermined conditions to form an easily detectable substance having the substituent, and to provide a substance applying the above binding, a substance capable of quickly and easily capturing a phosphorylated substance, and a capturing method as well as a method for detecting the captured substance.